Motor unit having a lubricant circuit

Abstract

A motor unit is provided having an electric motor and a transmission, which are mechanically joined together and arranged in a housing, wherein the motor unit comprises a lubricant circuit, which lubricates the electric motor and the transmission, wherein a lubricant pump is provided, having an outlet and at least two inlets for lubricant. Furthermore, a lubricant sump is provided, which is arranged beneath the electric motor and/or the transmission in the housing during use, having at least two suction points. A method is also provided for the circulation of lubricant in a motor unit.

1 . A motor unit, comprising:
 an electric motor and a transmission, which are mechanically joined together and arranged in a housing;   a lubricant circuit, which lubricates the electric motor and the transmission;   a lubricant pump having an outlet and at least two inlets for lubricant, wherein the outlet is connected by conduits to the electric motor and the transmission; and   a lubricant sump arranged beneath the electric motor and/or the transmission in the housing during use, and having at least two suction points separated from each other in a horizontal direction, and wherein each of the suction points is connected by a conduit to an inlet of the lubricant pump.   
     
     
         2 . The motor unit according to  claim 1 , wherein the lubricant sump is situated beneath the electric motor during use and a lubricant shell is arranged beneath the transmission during use, being provided to catch the lubricant from the transmission, and the transmission comprises at least one transmission gear, which dips partly into the lubricant caught in the lubricant shell, the transmission gear delivering lubricant from the lubricant shell to the lubricant sump during use. 
     
     
         3 . The motor unit according to  claim 2 , wherein the lubricant sump is situated above the lubricant shell in the vertical direction during use and a protrusion is arranged between the lubricant sump and the lubricant shell, which extends beyond the lubricant level in the lubricant sump in the vertical direction during use. 
     
     
         4 . The motor unit according to  claim 2 , wherein at least one lubricant guiding element is provided in the housing adjacent to the transmission gear, guiding the lubricant flow from the transmission gear to the lubricant sump. 
     
     
         5 . The motor unit according to  claim 1 , wherein the lubricant pump comprises an electric drive and is situated inside or outside the housing. 
     
     
         6 . The motor unit according to  claim 5 , wherein the lubricant pump is configured as an external gear pump, wherein two gears are provided, each of which suctions lubricant from one of the two inlets. 
     
     
         7 . The motor unit according to  claim 5 , wherein the lubricant pump is configured as a vane pump, wherein the vane pump comprises two suction openings which are staggered by  180 ° with respect to each other in the circumferential direction, each of which forms one inlet of the lubricant pump. 
     
     
         8 . The motor unit according to  claim 1 , wherein the lubricant sump has larger dimensions during use in the horizontal direction than in a vertical direction, wherein a length and a width of the lubricant sump in the horizontal direction is larger by at least a factor of  8  than a height in the vertical direction, and the suction points are situated respectively in the horizontal direction at a distance from an outer edge of the lubricant sump corresponding to as much as  20 % of the distance between two opposite outer edges in the horizontal direction. 
     
     
         9 . The motor unit according to  claim 1 , wherein a heat exchanger is arranged between the lubricant pump and the transmission and/or spray rings delivering lubricant to the electric motor are arranged next to the electric motor in the housing. 
     
     
         10 . The motor unit according to  claim 1 , wherein at least the electric motor has a coolant circuit different from the lubricant circuit. 
     
     
         11 . A method for the circulation of lubricant in a motor unit having: an electric motor and a transmission, which are mechanically joined together and arranged in a housing; a lubricant circuit, which lubricates the electric motor and the transmission; a lubricant pump having an outlet and at least two inlets for lubricant, wherein the outlet is connected by conduits to the electric motor and the transmission; and a lubricant sump arranged beneath the electric motor and/or the transmission in the housing during use, and having at least two suction points separated from each other in a horizontal direction, and wherein each of the suction points is connected by a conduit to an inlet of the lubricant pump, the method comprising:
 suctioning of lubricant from the lubricant sump, wherein the lubricant is suctioned from both suction points or from only one suction point by the lubricant pump, wherein the number of suction points used depends on the transverse acceleration acting on the lubricant during use;   transporting of the lubricant by the lubricant pump to the transmission and to the electric motor through conduits; and   conducting of the lubricant by gravity and/or centrifugal force through the transmission and the electric motor, the lubricant being caught in the lubricant sump after the lubricant passes through.